Painting: What did I do wrong?

[pappy]

Paint: Ace Rust Stop, mixed 8:2:1 with mineral spirits and hardener, sprayed with a Finish Line gun.

I've done several coats and this is the first time this has happened. The only element that changed was the hardener. I was using a hardener from NAPA. This time I used the hardener that was promoted by thecrazygreek. As you can see it did not lay down nice.

Any idea what happen? This is beyond orange peel.

 

[Texx]

Doubt its the gun looks like chemical reaction. changing components of your paint in progress is a giant no no. You either didn't allow enough flash time (doubtful), or you had a chemical reaction (highly likely). I'd say something in the new hardener is lifting the surface below. I only use regular automotive paint, but with auto paint, four coats is plenty. More is not necessarily better. You may be in serious trouble now....lots of sanding may be in your future. Hopefully that's not an all over coat! You may have to sand down to smooth surface and try sealing it with some DP 50 sealer from DuPont. About the only other possiblity would be something in your air. Are you using filtered air and did you switch hoses? In line oilers for air tools are death on paint, altho they usuall cause fish eyes.

 

[wob]

I'm guessing you used a spray gun and a compressor? Do you have a water remover in line on your compressor? It looks to me that those bumps may be water bubbles trapped under the paint. Can you pop them? Also, how much dust in the air where you painted?


EDIT: X2 on the lots of sanding in your future. : (

 

[pappy]

About the only other possibility would be something in your air. Are you using filtered air and did you switch hoses? In line oilers for air tools are death on paint, although they usually cause fish eyes.

No changes here. I have a filter at the compressor.

You may be in serious trouble now....lots of sanding may be in your future.

Yep, I figured lots of sanding now. I was just thinking about doing the "public" areas on the truck. The stuff underneath I'm not as concerned about. I didn't think about a reaction.

 

[okie]

looks like the surface wasn't cleaned totally before you sprayed the paint. The paint looks like it is reacting with another chemical or the surface wasn't wiped down well enough and looks to be dust or dirt particles.

 

[pappy]

looks like the surface wasn't cleaned totally before you sprayed the paint. The paint looks like it is reacting with another chemical or the surface wasn't wiped down well enough and looks to be dust or dirt particles.

OK, could wiping down with the mineral spirits do this?

 

[Texx]

Yes, you should only use prepsol or similar prior to paint. Lacquer thinner is used to clean the paint out of your gun. That should tell you it's solvent properties aren't helpful to your paint since only the primer would be a lacquer thinner base.

 

[Texx]

My bad, now i see that you do reduce it with thinner. Still, it's a solvent and could react with the paint it was put onto. How long since the previous coat to the one that gave you trouble?

 

[pappy]

There was a week between coats. I painted last Sunday, sanded yesterday (Saturday), wiped it down this morning, then painted about 2 hours later.

 

[thecrazygreek]

I am sorry to see this happen to you. I never had an issue using that hardner. It always layed down nice for me.


I would save yourself some time, and sand that down with 320, or 400.

 

[40Flipper]

I used mineral spirits to clean before and between coats and didn't have troubles. use a tack cloth as well to get all the little bits off of it before spraying.

 

[Texx]

I have definitely had poor results wiping down with lacquer thinner, in fact, it never came out well. Been a long long time since I'd done that, since I told myself never again. I think it's a combination of the two. Change in product, and lacquer thinner wipe down. After sanding, tack and respray with the original hardener should fix it.

 

[pappy]

Back at it today. I did make the observation that the 5108 hardener was not mixing with the mineral spirits. It seem to "float" in the bottom of the mixing cup under the mineral spirits. It was too late to try again, but lacquer thinner seemed to mix better with 5108 hardener. I rolled the paint on today instead of shooting through the sprayer and had the same results.

Any reason why I can't use the lacquer thinner to thin this paint? I seem to recall somebody used it on their project.

 

[cruiser88]

I have seen old paint do the same thing pappy....even right off the shelf

Get welbeka opinion on it also.